Clozapine, but not olanzapine or quetiapine, linked with higher perimyocarditis and HF risk

A recent population-based study published in Psychiatry Research by Eric Clapham and colleagues has studied concerns about associations between the use of clozapine, an antipsychotic medication, and cardiac adverse events. The study's findings highlight a significantly higher risk of perimyocarditis and heart failure among individuals using clozapine, raising important questions about the safety profile of this medication.

Researchers delved into Swedish national registers to identify patients aged 16 to 75 years who had received antipsychotic medications between 2005 and 2018. The study assessed the risk of perimyocarditis (pericarditis and/or myocarditis) within two months of starting the medication and heart failure (including cardiomyopathy) within three years. The analyses

utilized Cox regressions with time-varying exposure to estimate hazard rates and their corresponding 95% confidence intervals.

● The study cohort included a total of 201,045 individuals.

● Results unveiled a striking threefold increased risk of perimyocarditis during clozapine treatment compared to no antipsychotic treatment (HR 3.4, CI 1.6–7.3).

● While the absolute rate remained relatively low, the association raised concerns.

● The long-term risk of heart failure was also elevated among clozapine users (HR 1.3, CI 1.1–1.7).

● Treatment with olanzapine or quetiapine, both chemically related to clozapine, did not exhibit the same associations with increased risk of cardiac adverse events.

The findings from this study underscore the importance of monitoring individuals undergoing clozapine treatment for potential cardiac adverse events, particularly perimyocarditis and heart failure. These associations suggest the need for vigilant evaluation and management of patients on clozapine therapy, especially within the first few months of treatment. However, it's crucial to note that while the relative risks were heightened, the absolute rates of these events remained comparably low.

This population-based study illuminates the connection between clozapine, a widely used antipsychotic, and an elevated risk of cardiac adverse events. The identified associations with perimyocarditis and heart failure underscore the need for healthcare providers to be

vigilant when prescribing clozapine, particularly considering its unique risks. As researchers continue to explore these associations, medical professionals will gain valuable insights to ensure patient safety and effective treatment strategies.

Reference:

Clapham, E., Reutfors, J., Linder, M., Brandt, L., Sundström, J., & Bodén, R. (2023). The association between exposure to clozapine, olanzapine, and quetiapine and the outcomes perimyocarditis and heart failure: A population-based cohort study. Psychiatry Research, 326(115336), 115336. https://doi.org/10.1016/j.psychres.2023.115336